Load beam interlocking boss

ABSTRACT

A connection mechanism for connecting a pair of head suspension assemblies to a disc drive actuator arm in which the connection mechanism includes connection portions associated with respective load beams with such connection portions having cooperating, mating bosses extending into a mounting opening in the actuator arm and into interconnecting overlapping engagement with one another to result in an interference fit connection.

This is a continuation-in-part of application Ser. No. 460,574 filedJan. 3, 1990, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an improved magnetic headsuspension assembly (HSA) and more specifically to a low profilemechanical connection mechanism or assembly for connecting a pair ofhead suspension assemblies to an actuator arm.

2. Description of the Prior Art

Magnetic head suspension assemblies are used in magnetic disc storagedevices or disc drives for the purpose of positioning and supporting aread/write transducer head or slider at one end relative to a rotatingdisc. A common construction is to have a plurality of such rotatingdiscs which are spaced relative to one another about a common rotationalaxis. In a multiple disc system, a pair of oppositely disposed headsuspension assemblies are positioned between the discs, with one HSA ofeach pair associated with respective opposing sides of the adjacentdiscs. The end of the head suspension assembly opposite the slider isconnected to a rigid actuator arm. The memory density or memory capacityfor a given space and given track density for a multiple disc system isdetermined principally by the distance between the spaced discs. Thecloser the discs are spaced, the greater the memory density.Accordingly, there is and has been a need for reducing the disc spacingto thereby result in increased memory capacity.

Currently, a pair of head suspension assemblies are attached to a rigidactuator arm through the use of base plates positioned on opposite sidesof the arm. These base plates and the load beams to which they arewelded or otherwise connected, are part of the suspension assemblies andare either screwed or swaged to the support arm. In prior art screwconnections, small screws extend through holes in the base plates andarm and are retained on the opposite side by a threaded tap in the armor by a threaded nut plate as disclosed in U.S. Pat. No. 4,912,583issued to Hinlein on Mar. 27, 1990.

In prior art swage connections, the base plates each include an openingand a generally cylindrical projection or boss designed for extensioninto a corresponding hole in the actuator arm. A prior art swageconnection is disclosed in U.S. Pat. No. 4,829,395 issued to Coon on May9, 1989. In these prior swage connections, the thickness of the actuatorarm must be sufficient to accommodate the bosses of both base plates.Following initial assembly, a steel swaging ball or other means isforced through the openings in the respective bosses thereby deformingthe same and causing an interference fit between the outer cylindricalsurface of the bosses and the inner cylindrical surface of the openingin the actuator arm. Because- of a certain, predetermined minimum lengthrequirements of each of the bosses, the amount that the thickness of thesupport arm can be reduced is limited. Prior art screw connections havesimilar actuator arm thickness requirements. Because of theserequirements, the amount which the distance between the discs can bereduced is limited. Thus, the memory density of the unit is similarlylimited.

Alternative methods of achieving minimum disc spacing, less than thatprovided by screw or conventional swage connections, are by bonding,welding or otherwise permanently securing the head suspension assembliesdirectly to the actuator arm. Although this will permit furtherreduction of the width of the actuator arm, these methods generallyrequire expensive processes and induce a large loss when rework isneeded. In the event of a suspension assembly failure, the entireactuator arm must be discarded or a costly HSA removal process must beutilized.

Accordingly, there is a need for an improved head suspension assemblyand more particularly, an improved, low profile connection mechanism orassembly by which a pair of head suspension assemblies can be connectedto an actuator arm in a manner which reduces or minimizes the thicknessof the actuator arm, but which still permits individual HSA's or pairsof HSA's to be easily and inexpensively removed from the actuator armand replaced.

SUMMARY OF THE INVENTION

The connection mechanism or assembly of the present invention overcomesthe limitations of prior art connections by allowing the thickness ofthe actuator arm and thus the overall connection assembly to be reducedto a point where such thickness is no longer the limiting thickness fordetermining disc spacing. In so doing, the memory density for a givenmultiple-disc disc drive can be maximized, resulting in significantimprovement over prior swage or screw connections.

The present invention accomplishes the reduction in thickness byutilizing a unique connection assembly incorporating a pair of opposedinterlocking bosses having configurations which, when swaged or pressedtogether, permit the bosses to not only be secured to the actuator arm,but also secured to one another via an interference fit. In thisapplication, the term interference fit is intended to include aconnection resulting from frictional forces between two surfaces eithervia swaging or as a result of the configuration of the connectionelements alone. An interference fit is not intended to include athreaded connection.

More specifically, the connection assembly of the present inventionincludes a pair of opposed, corresponding base plates which are weldedor otherwise secured to a pair of load beams in a conventional manner.One of the base plates includes an outer cylindrical boss having anouter cylindrical surface adapted for insertion into and engagement withan opening in the actuator arm. The corresponding second base plateincludes an inner cylindrical boss having an outer cylindrical surfaceadapted for mating engagement with a portion of an inner cylindricalsurface of the outer boss. The inner boss of the preferred embodiment isalso provided with an inner cylindrical surface adapted for engagementby a swaging ball or tool to secure the respective bosses to one anotherand the outer boss to the actuator arm by an interference fit. In thepreferred embodiment, means are also provided in the respective outerand inner bosses for insuring engagement therebetween after swaging andmeans in the form of a lead-in surface to facilitate swaging. It is alsocontemplated, however, that the bosses can be configured to retain theload beams to the arm by the configuration of the bosses alone, withoutswaging. A further feature of the present invention contemplatesincorporating the interlocking elements into the load beams themselves,thus eliminating the need for the base plates.

The result is a connection assembly which permits significant reductionof the thickness of the actuator arm and connection components, whilestill maintaining sufficient resistance to torque and the ability toremove and replace individual head suspension assemblies without havingto discard the entire actuator arm.

A further feature of the present invention includes means to cap thehead suspension assemblies at the ends of a stack having one or moreintermediate actuator arms and corresponding pairs of head suspensionassemblies.

Accordingly, it is an object of the present invention to provide animproved connection assembly for connecting a pair of head suspensionassemblies to an actuator arm which does not restrict or limitreductions in disc spacing.

Another object of the present invention is to provide an improvedconnection assembly for connecting a pair of head suspension assembliesto an actuator arm which permits reduced disc spacing while securing theload assembly to the actuator arm with no significant reduction intorque resistance.

A further object of the present invention is to provide a connectionassembly for connecting a pair of head suspension assemblies to anactuator arm which permits reduced disc spacing while retaining theability to replace one or both of the head suspension assemblies,without destroying or discarding the entire actuator arm or other HSA's.

A still further object of the present invention is to provide animproved disc drive system having multiple discs and an improvedconnection mechanism for connecting a pair of head suspension assembliesto an actuator arm which allows for minimum disc spacing and thusmaximum memory density.

A still further object of the present invention is to provide a magnetichead suspension assembly for a multiple disc system having a stack ofhead suspension assemblies and means for capping the end suspensionassemblies in such stack.

These and other objects of the present invention will become apparentwith reference to the drawings, the description of the preferredembodiment and the appended claims.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective, broken apart view of a pair of head suspensionassemblies incorporating the connection assembly of the presentinvention.

FIG. 2 is a side view of a portion of a disc drive system with portionsbroken away incorporating a pair of head suspension assemblies andassociated connection mechanism of the present invention.

FIG. 3 is a top view of the connection assembly portion of the deviceillustrated in FIG. 2.

FIG. 4 is a view, partially in section as viewed along the section line4--4 of FIG. 3.

FIG. 5 is an enlargement, in section, showing the construction detailsof the interlocking pair of connection bosses.

FIG. 6 is a broken apart view of an alternate connection assembly of thepresent invention.

FIG. 7 is a side fragmentary view with parts broken away of a disc drivesystem incorporating the connection assembly of FIG. 6 in assembledform.

FIG. 8 is a side fragmentary view with parts broken away of a furtheralternate connection assembly.

FIG. 9 is a side fragmentary view with parts broken away of a stillfurther alternate connection assembly.

FIGS. 10, 11, 12 and 13 are side fragmentary views with parts brokenaway of a carriage for a multiple disc drive having a stack of headsuspension assemblies and illustrating various alternate embodiments forcapping the end head suspension assemblies in such stack.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A pair of head suspension assemblies mounted to an actuator arm in amultiple disc drive environment in accordance with the present inventionis shown best in FIG. 2. As illustrated, a pair of head suspensionassemblies 10 and 11 includes one end connected to a rigid actuator arm13 and an outer, second end positioned for movement between a pair ofspaced discs 22 and 23. In general, the head suspension assembly 10includes a load beam 12, a base plate or connection member 15 connectedto the load beam at one end and a slider or read/write transducer head20 connected to the load beam 12 at its other end via an appropriateflexure. The head suspension assembly 11 includes the load beam 14, abase plate or connection member 16 connected to the load beam 14 at oneend and a slider or read/write transducer head 21 connected to the loadbeam 14 at the other end via a flexure.

As illustrated best in FIGS. 1 and 2, each of the load beams 12 and 14comprises a generally flat thin structure having a connection opening 39and 40, respectively at one end and includes a pair of side rails 18 and19, respectively, to provide desired rigidity and load supportcapability to the structure. Both the load beam 12 and the load beam 14and their respective transducer heads 20 and 21 comprise conventionalelements known in the art. Preferably the load beams 12 and 14 areconstructed of stainless steel. It should be noted that in the preferredembodiment, the rails 18 and 19 face away from one another in order toaccommodate the reduced actuator arm thickness made possible by theconnection assembly of the present invention. However, it iscontemplated that the rails 18 and 19 could, if desired, face inwardlyas well, providing the arm 13 is of sufficient thickness.

Associated with each of the load beams 12 and 14 is a base plate orconnector element 15 and 16, respectively. Each base plate 15 and 16includes a center opening and a mating boss 26 and 28, respectively(FIG. 4). As will be described in greater detail below, the matingbosses 26 and 28 are designed for interconnection with one another aswell as interconnection with the actuator arm 13. In the preferredembodiment, the base plates 15 and 16 include generally flat mountingsurface portions 27 and 17, respectively. The respective bosses 26 and28 extend outwardly from the mounting surface portions 27 and 17 atgenerally right angles. Preferably the base plates 15 and 16 are weldedor otherwise secured to their respective load beams 12 and 14 in amanner conventional in the art. When so connected, the boss 26 of thebase plate 15 extends through the opening 39, while the boss 28 of thebase plate 16 extends through the opening 40.

The actuator arm 13 is connected or formed with a conventional carriage(not shown) and includes a head suspension assembly connecting portion24. In the preferred embodiment, the connecting portion 24 is reduced inthickness to take advantage of the arm thickness reducing features ofthe present invention. It is contemplated, however, that the thicknessof the entire rigid arm 13 could be reduced to the thickness of theportion 24 if desired. It is contemplated that certain advantages of theconnection mechanism of the present invention can also be obtained bynot reducing the thickness of the arm 13. The connecting portion 24 isprovided with a pair of opposed mounting surfaces 33 and a mountingopening 25 to receive the bosses 26 and 28 from the base plates 15 and16 as will hereinafter be described. The actuator arm thicknessdimension d¹ (FIG. 4) is defined by the distance between the opposedmounting surfaces 33. In the preferred embodiment the arm 13 and portion24 is constructed of magnesium or aluminum or some similar elasticallydeformable material.

As illustrated best in FIGS. 4 and 5, the base plates 15 and 16 areprovided with corresponding mating bosses 26 and 28. More specifically,the base plate 16 includes an outer boss 28 having an outer generallycylindrical arm engaging surface 29 closely approximating and conformingto the configuration and dimensions of the inner cylindrical surface ofthe mounting opening 25 in the portion 24. Thus, when the boss 28 isinserted into the opening 25, the surface 29 is in close registrationwith the surface 25. The boss 28 also includes an inner diameter orcylindrical boss engaging surface 30 which is generally parallel to thecylindrical surface 29. In the preferred structure, the boss 28 is alsoprovided with a second inner surface or back bore 35 having a diameteror cross-sectional dimension greater than the diameter of the surface30. A recess or chamfer portion 36 is provided to join the surfaces 30and 35. During the swaging procedure in accordance with the preferredembodiment, a portion of the material from the inner boss is caused toflow into the recessed area 36, thus assisting in the connection betweenthe inner 26 and outer 28 bosses. It is contemplated, however, that manyof the advantages of the present invention can be realized without theaddition of the recess 36 and the inner surface 35. In such a structure,the inner surface 30 would extend throughout the entire height of theboss 28. The height d² of the outer boss 28 is defined by the distancethe boss 28 extends outwardly from the surface mounting portion 17.

The base plate 15 is provided with an inner boss 26 having an outercylindrical boss engaging surface 31 and an inner cylindrical swagingsurface 32 defining a swaging opening. The boss engaging surface 31 isadapted for insertion into and close registration with the inner bossengaging surface 30. Thus, the configuration and cross-sectionaldimensions of the surface 31 approximates and conforms substantiallywith the configuration and dimensions of the inner surface 30. In thepreferred embodiment, the outer surface 31 extends past the recessedportion 36 so that as deformation of the boss 26 occurs during theswaging process hereinafter described, a portion of the material fromthe boss 26 will expand and flow into and interlock with the recessedportion 36. In the event the recess 36 is eliminated, the bosses 26 and28 are retained with respect to one another solely by the interferencefit between them.

The inner cylindrical swaging surface 32 is generally parallel with thesurface 31 and is adapted for engagement by a swaging ball or tool via amethod known in the art. The boss 26 includes a second inner surface orback bore 34 having a diameter greater than the diameter of the surface32. A tapered or lead-in swaging surface portion 38 joins the surfaces34 and 32 to provide a lead-in surface for the swaging ball or tool ashereinafter described. The height d³ of the inner boss 26 is defined bythe distance the boss 26 extends outwardly from the surface mountingportion 27.

When assembled in the manner illustrated in FIG. 4, prior to swaging,the outer surface 29 is in close proximity and registration with theinner surface of the mounting opening 25, while the respective bossswaging surfaces 30 and 31 are in close proximity and registration withone another. When so assembled, it can be seen that the thickness d¹ ofthe connecting portion 24 of the arm 13 plus the thickness of the loadbeams is less than the sum of the heights (d² +d³) of the bosses 26 and28. Thus, when assembled as illustrated, the respective bosses 26 and 28overlap with one another. Preferably, using standard load beamthicknesses of about 0.003 inch, the sum of the heights d² and d³ shouldbe approximately two times greater than the arm thickness d¹ andpreferably at least about 1.1 times greater. Preferably the connectorelements 15 and 16 and integrally formed bosses 26 and 28 areconstructed of stainless steel, although it is contemplated that theycould be made from other materials as well.

The above described connection assembly can be completed by swaging inaccordance with a process conventional in the art. This commonlyinvolves physically forcing a swaging ball or swaging tool through theswaging opening defined by the inner swaging surface 32 so that anoutward swaging force is exerted on the inner boss 26. This outwardforce causes the bosses 26 and 28 to deform slightly with respect to oneanother to form an interference fit therebetween and also causes theboss 28 and portion 24 to deform slightly, thereby resulting in aninterference fit between the boss 28 and mounting opening 25 as well.Preferably, the size of the swaging ball or tool or the outward forcegenerated against the inner boss 26 should be such that the deformationof the opening 25 is an elastic deformation. This will enable the bossesand thus the respective load assemblies to be replaced without having toreplace the entire actuator arm. During the swaging process, thedeformation of the bosses 26 and 28 is generally a permanent or plasticdeformation. Although the opening 25 and the bosses 26 and 28 arepreferably cylindrical, it is contemplated that other configurations mayalso be utilized while still achieving the benefits of the presentinvention.

In addition to a swaging connection between the outer boss 28 and thesupport arm portion 24 and between the outer boss 28 and the inner boss26 as described above, it is contemplated that such elements can also beconnected and retained relative to one another by a press orinterference fit, without swaging. In such a structure, the retainingforce results from the frictional forces between the surfaces of therespective components due to the configuration of the components alone,without deformation by a swaging ball or tool. Examples of structuresutilizing an interference fit, without swaging, are illustrated in FIGS.6-9.

FIGS. 6 and 7 illustrate one such embodiment of a connection mechanismfor retaining a pair of load beams 12 and 14 to one end of a support arm24. FIG. 6 is a broken apart view of such a mechanism, while FIG. 7illustrates such mechanism in its assembled form. The mechanism of FIGS.6 and 7 includes a first connection member 45 having a generally flatmounting surface similar to the connection member 15 and a hollowinterference fit boss 48 extending outwardly from such mounting surface.The boss 48 includes an outward bulge or convex portion near itsmidpoint, a corresponding concave portion opposite to the convex portion49, an inwardly extending lead-in edge portion 50 and an outer end edge51. The preferred embodiment illustrates the boss 48 being hollowthroughout, however, only a portion sufficient to receive an inner bossneeds to be hollow.

The mechanism of FIG. 6 also includes a second connection member 46having a flat mounting surface and an inner interference fit boss 52extending outwardly from such surface. The boss 52 includes a convexportion 54 near the midpoint of the boss 52 and an inwardly inclinedlead-in edge 55 near its outer end. To assemble the mechanism of FIGS. 6and 7, the load beams 12 and 14 are positioned on opposite sides of thesupport arm 24 as shown, with the connection openings of the load beams12 and 14 aligned with the support arm opening 25 or the connectionmembers 45 and 46 connected with the load beams 12 and 14 in a mannerknown in the art. The connection member 45 is then assembled byinserting the outer boss 48 into the opening 25. During this assembly,the lead-in edge 50 engages an edge of the opening 25 to properly alignand guide the boss 48 into the opening 25. The connection member 46 isassembled by inserting the inner boss 52 into the hollow interiorportion of the boss 48. During this assembly, the lead-in edge of 55engages the outer edge 51 of the boss 48 to properly align and guide theconnection member 46 into proper position. The two connection members 45and 46 are then manually or otherwise pressed together so that theconvex portion 54 of the boss 52 seats within the inner concave portionof the boss 48.

In the assembled position, the convex portion 49 of the boss 48frictionally engages the side wall of the opening 25 and the innersurface of the boss 48 and the outer surface of the boss 52 frictionallyengage one another. In such mechanism, it is essential that the innerends of the bosses 48 and 52 overlap to some extent with one another toprovide the interference fit between such bosses. Also, the dimensionsof the bosses 48 and 52 are such that upon insertion, they willfrictionally engage via an interference fit, the opening 25 and theinner surface of the boss 48, respectively. It is also preferable forthe bosses to have limited flexibility to result in the interferencefit.

In the interference fit mechanism of FIGS. 6 and 7 and the swageconnection mechanism of FIGS. 4 and 5, it is contemplated thatconnection members would be utilized to connect the load beams 12 and 14to the support arm 24. However, it is also contemplated that the innerends of the load beams themselves can be constructed to incorporate aconnection mechanism, thus eliminating the connection members 15 and 16of FIGS. 4 and 5 and the connection members 45 and 46 of FIGS. 6 and 7.Such mechanism results in significant reduction in the overall thicknessof the connection assembly. In FIG. 8, the load beams 12a and 14apositioned on opposite sides of the support arm 24 have been modified toincorporate a connection mechanism directly into the load beamsthemselves. Specifically, the load beam 12a has been modified to includea hollow outer boss 53 having an outer surface for engagement with theinner surface of the mounting opening 25, while the load beam 14a hasbeen modified to include an inner boss 57 having an outer surface forengagement with the inner surface of the boss 53. The bosses 53 and 57are similar to the bosses 48 and 52 of FIGS. 6 and 7, except that thebosses 53 and 57 are formed directly in the load beams 12a and 14a.Also, similar to the connection mechanism of FIGS. 6 and 7, the bosses53 and 57 of FIG. 8 must be sufficiently long to result in at least apartial overlap and must have dimensions facilitating a sufficientfrictional engagement with their respective engagement surfaces.

FIG. 9 illustrates a further embodiment of an interference fitconnection mechanism. In FIG. 9, the connection members 56 and 60 aresimilar to the connection members 45 and 46 of FIG. 7, except that therespective bosses 58 and 61 have generally straight edges. The bosses 58and 61 of FIG. 9 are, however, provided with tapered lead-in edges 59and 62, respectively to facilitate proper alignment and insertion of thebosses 58 and 61. In the embodiment of FIG. 9, the outer surface of theboss 58 is in frictional engagement with the inner surface of theconnection opening 25, while the outer surface of the boss 61 and theinner surface of the boss 58 are in frictional engagement with oneanother.

Reference is next made to FIGS. 10, 11, 12 and 13 illustrating acarriage 39 for a multiple disc drive. The carriage 39 comprises aplurality or stack of head suspension assemblies 10 and 11 positioned onopposite sides of a plurality of discs and various alternate means forcapping the end head suspension assemblies in such stack. As usedherein, the term capping refers to the procedure of connecting the endsuspension assemblies to their respective end support arms. The carriage39 in each of FIGS. 10, 11, 12 and 13 is provided with a plurality ofactuator or support arms including first and second end support arms 13aand 13c and one or more intermediate support arms 13b. A pair of headsuspension assemblies 10 and 11 are connected with each of theintermediate actuator arms 13b in the manner shown in FIGS. 1-5 or 6-9.However, only a single suspension assembly is connected to each of theend support arms 13a and 13c. FIGS. 10-13 show various alternatemechanisms for accomplishing this connection.

In FIG. 10, the top assembly 11 is connected to the bottom mountingsurface of the arm 13a by using a connection member 15 in combinationwith the connection member 16 as shown. Such member 15 includes an innerboss 26 which is connected to the corresponding connection member 16which is in turn connected directly to the support arm 13a. The bottomassembly 10 in FIG. 10 is similarly connected to the top mountingsurface of its end support arm 13c by using a connection member 15 incombination with the connection member 16. Thus, both the top and bottomassemblies 11 and 10 in FIG. 10 are capped by use of the connectionmembers 15 and 16, respectively. An advantage of this particular cappingmechanism is that the connection members 15 and 16 are the same as areused to connect the assemblies to the intermediate support arms 13b.Thus, no additional parts are required. It does, however, result in someoverall increase in carriage height due to the thickness of the members15 and 16. In each of FIGS. 10-13 where connection members are used itis contemplated that connection can be accomplished by swaging or solelyby an interference fit.

In FIG. 11, the top assembly 11 is connected to the arm 13a in a manneridentical to the top assembly 11 in FIG. 10. The bottom assembly 10 inFIG. 11, however, is connected to its support arm 13c by connecting theboss 26 directly to the mounting hole in the arm 13c. Because of this,the mounting opening in the arm 13c must be smaller than the mountingholes in the outer arms 13a and 13b. Although this embodiment results ina decrease in overall carriage height by an amount equal to thethickness of the member 16, it does require a second drill pass ifswaging is utilized.

When assembling the carriage 39 illustrated in FIG. 10, an opening isdrilled in the actuator arms 13a and 13b to receive the pair of mountingplates 15 and 16. Since these openings are all of the same size, theycan be formed with a single drill pass. However, because the connectionof the base plate 15 to the actuator arm 13c requires a smaller opening,this must be formed with a second drill pass.

FIG. 12 illustrates a further mechanism for capping the end suspensionassemblies. In FIG. 12, both end suspension assemblies are capped off byconnecting a base plate member 15 directly to the respective actuatorarm 13a and 13c. This results in a decrease in overall carrier heightcompared to that of both FIGS. 10 and 11. However, because the mountingopenings needed in the intermediate actuator arms 13b are larger thanthe mounting openings needed in the arms 13a and 13c, one of the arms13a or 13c, must be removable. This allows the larger holes in the arms13b to be drilled. After this first drilling, the smaller holes in thearms 13a and 13c can be drilled. The assemblies 10 and 11 can then beswaged or otherwise connected to their respective arms 13a, 13b and 13c,followed by connection of the arm 13a to the carriage 39 by the screw44.

A still further means for capping the head suspension assemblies in acarriage having a stack of such assemblies is by securing the end loadbeams 11 and 10 directly to their respective actuator arms 13a and 13cby welding, gluing with an adhesive or the like as shown in FIG. 13.When this method is utilized, at least one of the arms 13a and 13c mustbe removably secured to the carriage 39 or a drill and access hole mustbe provided in at least one of the arms 13a and 13c. It should be notedthat any one of the means of capping the end assemblies shown in FIGS.10-13 can be utilized, either on one or both ends of the carriage.Further, it is contemplated that any of the swaging connectionsillustrated in FIGS. 1-5 or any of the interference fit configurations,without swaging, as illustrated in FIGS. 6-9 may be utilized.

The above described connection assembly described in FIGS. 1-5 and 6-9with respect to support arms 13b and in FIGS. 10-13 with respect to endsupport arms 13a and 13c permits the support arm thickness, and thus theoverall carriage height, to be significantly reduced. This in turnallows the load beams to be placed closer together to accommodate closerdisc spacing and increased memory density.

Although the description of the preferred embodiment has been quitespecific, it is contemplated that various modifications could be madewithout deviating from the spirit of the present invention. Accordingly,it is intended that the scope of the present invention be dictated bythe appended claims rather than by the description of the preferredembodiment.

I claim:
 1. A connection assembly for connecting a load beam to anactuator arm in a disc drive comprising:a first member having a firsthollow cylindrical deformable boss, said first boss sized and adaptedfor being closely fitted both within a connection opening of a load beamand within a connection opening of an actuator arm from a first sidethereof; and a second member having a second hollow cylindricaldeformable boss, sized and adapted for being closely and securelynest-fitted within the first boss, when the first boss is fitted bothwithin the connection opening of the first load beam and within theconnection opening of the actuator arm from a side thereof; whereby, theclose nest-fit between the bosses retains the load beam to the actuatorarm.
 2. A connection assembly according to claim 1, wherein the closenest-fit between the bosses is transformed to an interlockinginterference fit by forcing a swaging tool into the second boss anddeforming both bosses.
 3. A connection assembly according to claim 1,wherein the second boss is further sized and adapted to closely fit bothwithin a connection opening of a second load beam and within theconnection opening of the actuator arm.
 4. A connection assemblyaccording to claim 3, wherein the close fit between the bosses istransformed into an interlocking interference fit by forcing a swagingtool into the second boss and deforming both bosses.
 5. A connectionassembly according to claim 1, wherein lead-in surfaces of the bossesare curved to facilitate insertion of a swaging tool.
 6. A connectionassembly for connecting a load beam to an actuator arm in a disc drivecomprising:a first member having a first hollow cylindrical deformableboss of a first perpendicular height, sized and adapted for closelyfitting both within a connection opening of a load beam and within anactuator arm opening from a proximal side thereof, said actuator armopening located in a reduced perpendicular height portion of saidactuator arm; and a second member having a second hollow cylindricaldeformable boss of a second perpendicular height, sized and adapted forclosely and securely nest-fitting within the first boss, when the firstboss is fitted both within the connection opening of the first load beamand within the actuator arm opening from a distal side thereof; wherebythe perpendicular height of the reduced height actuator arm portion isless than the sum of the perpendicular heights of the bosses, therebyassuring that the close nest-fit between the bosses securely retains theload beam to the actuator arm.
 7. A connection assembly according toclaim 6, wherein the bosses are formed with corresponding outward bulgesto facilitate an interference fit therebetween.
 8. A connection assemblyaccording to claim 6, wherein the close nest-fit between the bosses isreinforced by forcing a swaging tool into the second boss, deformingboth bosses into an interference fit.
 9. A connection assembly accordingto claim 6, wherein the second boss is further sized and adapted toclosely fit both within a connection opening of a second load beam andwithin the connection opening of the actuator arm.
 10. A connectionassembly according to claim 9, wherein the close fit between the bossesis reinforced by forcing a swaging tool into the second boss, deformingboth bosses into an interference fit.
 11. A connection assemblyaccording to claim 6, wherein lead-in surfaces of the bosses are curvedto facilitate entry of a swaging tool.